Natural Calamities (Group 8)

Natural CalamitiesAn Environmental Engineering Report

Natural Calamity

• Also referred to as, natural disaster, is defined as a hazard which occur naturally, that is a disaster that is not brought by acts of human beings.

Definition

• Or simply an event of nature that takes human lives and destroys properties.

Categories of Natural Disaster

1. Geological Disaster

Types of Natural Disaster

2. Hydrological Disaster3. Meteorological Disaster4. Fires5. Health Disaster

6. Space Disaster

Geological Disasters

• Avalanche• Earthquake• Volcanic Eruption

AVALANCHE• Is a sudden rapid flow

of snow down a slope, occurring when either natural triggers or human activity causes a critical escalating transition from the slow equilibrium evolution of the snow pack.

Definition

AVALANCHE

• Avalanches are primarily composed of flowing snow, and are distinct from mudslides, rock slides, and serac collapses on an icefall.

Description

Classifications of Avalanche

1. Loose Snow Avalanche

Classification of Avalanche

occur in freshly fallen snow that has a lower density and are most common on steeper terrain


2. Slab Avalanche


account for around 90% of avalanche-related fatalities, and occur when there is a strong, cohesive layer of snow known as a slab.

These are usually formed when falling snow is deposited by the wind on a lee slope, or when loose ground snow is transported elsewhere.


3. Wet Snow / Isothermal Avalanche


which occurs when the snow pack becomes saturated by water.

When the percentage of water is very high they are known as slush flows and they can move on very shallow slopes.


4. Powder Snow Avalanche


is a powder cloud that forms when an avalanche accelerates over an abrupt change in slope, such as a cliff band, causing the snow to mix with air.

Avalanche Avoidance

• Prevention1. Active Preventive Measures

- reduce the likelihood and size of avalanches by disrupting the structure of the snow pack

a. traveling on a snow pack as snow accumulates

b. explosives

Avalanche Avoidance

• Prevention2. Passive Preventive Measures

- reinforce and stabilize the snow pack

a. Snow fences and light walls

b. Trees

Snow fences in Switzerland

Avalanche Avoidance

• Safety in Avalanche Terrain Terrain management

- involves reducing the exposure of an individual to the risks of traveling in avalanche terrain by carefully selecting what areas of slopes to travel on.

Avalanche Avoidance

• Safety in Avalanche Terrain Group management

- is the practice of reducing the risk of having a member of a group, or a whole group involved in an avalanche. Minimize the number of people on the slope, and maintain separation.

Avalanche Avoidance

• Safety in Avalanche Terrain Risk Factor Awareness

- in avalanche safety, it requires gathering and accounting for a wide range of information such as the meteorological history of the area, the current weather and snow conditions, and equally important the social and physical indicators of the group.

Avalanche Avoidance

• Safety in Avalanche Terrain Leadership

- Leadership in avalanche terrain requires well defined decision making protocols that use the observed risk factors.

Human Survival and Avalanche Rescue

• Search and Rescue Equipments

a. Avalanche Cordsb. Beaconsc. Probesd. Shovelse. RECCO Rescue Systemf. Avalungg. Avalanche Airbags



• Self-rescue

• Companion Rescue• Organized Rescue



There are 4 primary goals of any rescue operation and in organized rescue the goals can be initiated simultaneously.


1. Immediate search: get rescuers to the site; find and uncover buried victims



2. Medical: care for victims and companions

3. Transport/evacuation: transport rescuers in quickly and safely; get victims out and to advanced medical care; return rescuers safely

4. Support/Logistics: care for rescuers in the field (food, shelter, rest and replacement)

A Blackhawk helicopter as the crew prepares to evacuate tourists stranded by an avalanche in Galtür, Austria, on February 25, 1999.

Avalanche security, search and rescue equipment (left to right): avalanche airbag system, collapsed probe, shovel, avalanche transceiver

EARTHQUAKE• (also known as a quake, tremor

or temblor) is the result of a sudden release of energy in the Earth’s Crust that creates seismic waves.

Definition

• The vibrations may vary in magnitude. The underground point of origin of the earthquake is called the "focus". The point directly above the focus on the surface is called the "epicenter".

Earthquake Fault Types3 Main Types of Faults That May Cause An Earthquake

1. Normal Faults- occur mainly in areas where the

crust is being extended such as a divergent boundary

- Earthquakes associated with normal faults are generally less than magnitude 7.


2. Reverse (Thrust) Faults- occur in areas where the crust is

being shortened such as at a convergent boundary.

- Associated with most powerful earthquakes, including almost all of those of magnitude 8 or more


3. Strike-Slip Faults- are steep structures where the

two sides of the fault slip horizontally past each other.

- can produce major earthquakes up to about magnitude 8

Earthquake Clusters• Aftershocks

- An aftershock is an earthquake that occurs after a previous earthquake, the main shock.

- Aftershocks are formed as the crust around the displaced fault plane adjusts to the effects of the main shock.

Earthquake Clusters• Earthquake Swarms

- Earthquake swarms are sequences of earthquakes striking in a specific area within a short period of time. They are different from earthquakes followed by a series of aftershocks by the fact that no single earthquake in the sequence is obviously the main shock, therefore none have notable higher magnitudes than the other.

Earthquake Clusters• Earthquake Storms

- Sometimes a series of earthquakes occur in a sort of earthquake storm, where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes.

- Similar to aftershocks but on adjacent segments of fault.

Effects of EarthquakesThe effects of earthquakes include, but are not

limited to, the following:1. Shaking and ground rupture2. Landslides and Avalanches3. Fires4. Soil Liquefaction5. Tsunami6. Floods7. Loss of Life8. Damage to Property

PreparationToday, there are ways to protect and prepare possible

sites of earthquakes from severe damage, through the following processes:

a. Earthquake engineering

b. Earthquake Preparednessc. household seismic safetyd. seismic retrofite. seismic hazard f. mitigation of seismic motiong. earthquake prediction

VOLCANIC ERUPTIONVolcanoes can cause widespread

destruction and consequent disaster through several ways. A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface.

Definition

Plate Tectonics

- a theory that ascribes continental drift, volcanic and seismic activity, and the formation of mountain belts to moving plates of the Earth's crust supported on less rigid mantle rocks.

Plate Tectonics1. Divergent Plate Tectonics

- At the mid-oceanic ridges, two tectonic plates diverge from one another. New oceanic crust is being formed by hot molten rock slowly cooling and solidifying.

- Most divergent plate boundaries are at the bottom of the oceans, therefore most volcanic activity is submarine, forming new seafloor.

Plate Tectonics2. Convergent Plate Tectonics

- Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate submerges under the continental plate forming a deep ocean trench just offshore.

Plate Tectonics3. "Hot Spots"

- "Hotspots" is the name given to volcanic provinces postulated to be formed by mantle plumes.

- These are postulated to comprise columns of hot material that rise from the core-mantle boundary.

Types of Volcanoes1. Shield Volcanoes

- so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent, but not generally explode catastrophically.

- more common in oceanic than continental settings.

Types of Volcanoes2. Stratovolcanoes (Composite Volcanoes)

- are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that give rise to the name.

- created from several structures during different kinds of eruptions.

- Strato/composite volcanoes are made of cinders, ash and lava.

Types of Volcanoes3. Supervolcanoes

- is a large volcano that usually has a large caldera and can potentially produce devastation on an enormous, sometimes continental, scale.

- the most dangerous type of volcano.

Types of Volcanoes4. Submarine Volcanoes

- are common features on the ocean floor.

- Some are active and, in shallow water, disclose their presence by blasting steam and rocky debris high above the surface of the sea.

Types of Volcanoes5. Subglacial Volcanoes

- develop underneath icecaps.

- They are made up of flat lava which flows at the top of extensive pillow lavas and palagonite. When the icecap melts, the lavas on the top collapse, leaving a flat-topped mountain.

Types of Volcanoes6. Mud Volcanoes

- Mud volcanoes or mud domes are formations created by geo-excreted liquids and gases, although there are several processes which may cause such activity.

Classification of Volcanoes1. Active

- those that erupt regularly

2. Extinct- those that have not erupted in historical times

3. Dormant- those that have erupted in historical times but are now quiet

List of Notable Avalanches

Rank Death toll (estimate) Event Location Date

1 50,0001970 Huascarán avalanche;

triggered by the 1970 Ancash earthquake

Peru 1970

2 4,000 1962 Huascarán avalanche Peru 1962

3 265 Winter of Terror Austria-Switzerland 1951

4 172 2010 Salang avalanches Afghanistan 20105 125 Kolka-Karmadon rock ice slide Russia 2002

List of Notable Avalanches

Rank Death toll (estimate) Event Location Date

6 102 2010 Kohistan avalanche Pakistan 2010

7 96 Wellington, Washington avalanche

United States 1910

8 90 Frank Slide Canada 19039 62 1910 Rogers Pass avalanche Canada 1910

10 59 1993 Bayburt Üzengili avalanche Turkey 1993

List of Deadliest EarthquakesRank Name Date Location Fatalities Magnitude

1 "Shaanxi" January 23, 1556 Shaanxi, China 820,000–830,000 (est.) 8.0 (est.)

2 "Tangshan" July 28, 1976 Tangshan, China

242,419–779,000 7.5–7.8

3 "Antioch" May 21, 525

Antioch, Turkey (then

Byzantine Empire)

250,000 8.0 (est.)

4 "Gansu" December 16, 1920 Ningxia–Gansu, China 235,502 7.8

5 "Indian Ocean" December 26, 2004

Indian Ocean, Sumatra, Indonesia

230,210 9.1–9.3

List of Deadliest EarthquakesRank Name Date Location Fatalities Magnitude

6 "Aleppo" October 11, 1138 Aleppo, Syria 230,000 Unknown

7 "Haiti" January 12, 2010 Haiti

222,570 (Haitian sources)

50,000–92,000 (non-Haitian

sources)

7.0

8 "Damghan" December 22, 856 Damghan, Iran 200,000 (est.) 7.9 (est.)

9 "Ardabil" March 22, 893 Ardabil, Iran 150,000 (est.) Unknown

10 "Great Kantō" September 1, 1923 Kantō region,

Japan 142,000 7.9

List of Volcanic EruptionsRank Death toll Event Location Date

1 92,000 Mount Tambora Indonesia April 10,

1815

2 36,000 Krakatoa Indonesia August 26–27, 1883

3 33,000 Mount Vesuvius

Pompeii and Herculaneum, Italy August 24, 79

4 29,000 Mount Pelée Martinique May 7 or May 8, 1902

5 23,000Nevado del

Ruiz (Armero tragedy)

Colombia November 13, 1985

List of Volcanic EruptionsRank Death toll Event Location Date

6 15,000 Mount Unzen Japan 17927 10,000 Mount Kelut Indonesia 15868 9,350 Laki Iceland June 8, 17839 6,000 Santa Maria Guatemala 1902

10 5,115 Mount Kelut Indonesia May 19, 1919

Hydrological Disasters

• Floods• Limnic Eruptions• Tsunami

FLOODS

• is an overflow of an expanse of water that submerges land.

Definition

• The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water.

Principal Types and Causes1. Riverine

a. Slow kinds: Runoff from sustained rainfall or rapid snow melts exceeding the capacity of a river's channel. Causes include heavy rains from monsoons, hurricanes and tropical depressions, foreign winds and warm rain affecting snow pack. Unexpected drainage obstructions such as landslides, ice, or debris can cause slow flooding upstream of the obstruction.

Principal Types and Causes1. Riverine

b. Fast kinds: includes flash floods resulting from convective precipitation (intense thunderstorms) or sudden release from an upstream impoundment created behind a dam, landslide, or glacier.

Principal Types and Causes2. Estuarine

- Commonly caused by a combination of sea tidal surges caused by storm-force winds. A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category.

3. Coastal- Caused by severe sea storms, or as a result of another hazard (e.g. tsunami or hurricane). A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category.

Principal Types and Causes4. Catastrophic

- Caused by a significant and unexpected event e.g. dam breakage, or as a result of another hazard (e.g. earthquake or volcanic eruption).

5. Human-induced

- Accidental damage by workmen to tunnels or pipes.

Principal Types and Causes6. Muddy

- A muddy flood is produced by an accumulation of runoff generated on cropland. Sediments are then detached by runoff and carried as suspended matter or bed load.

- Muddy floods are therefore a hill slope process, and confusion with mudflows produced by mass movements should be avoided.

Principal Types and Causes7. Others

• Floods can occur if water accumulates across an impermeable surface (e.g. from rainfall) and cannot rapidly dissipate (i.e. gentle orientation or low evaporation).

• A series of storms moving over the same area.• Dam-building beavers can flood low-lying

urban and rural areas, often causing significant damage.

Effects1. Primary effects

• Physical Damage

- Can damage any type of structure, including bridges, cars, buildings, sewerage systems, roadways and canals.

Effects2. Secondary effects

• Water supplies

- Contamination of water. Clean drinking water becomes scarce.

• Diseases- Unhygienic conditions. Spread of water-

borne diseases.

Effects2. Secondary effects

• Crops and food supplies - Shortage of food crops can be caused

due to loss of entire harvest.• Trees- Non-tolerant species can die from

suffocation.• Transport- Transport links destroyed, so hard to get

emergency aid to those who need it.

Effects3. Tertiary/Long-Term effects

• Economic

– Economic hardship, due to: temporary decline in tourism, rebuilding costs, food shortage leading to price increase, etc.

BenefitsFloods (in particular the more frequent or smaller

floods) can also bring many benefits, such as:• Recharging ground water• Making soil more fertile and providing nutrients

in which it is deficient.• Flood waters provide much needed water

resources in particular in arid and semi-arid regions where precipitation events can be very unevenly distributed throughout the year.

Benefits

• Flooding adds a lot of nutrients to lakes and rivers which leads to improved fisheries for a few years, also because of the suitability of a floodplain for spawning.

• Freshwater floods in particular play an important role in maintaining ecosystems in river corridors and are a key factor in maintaining floodplain biodiversity.

Benefits

• The viability for hydrological based renewable sources of energy is higher in flood prone regions.

• Fish like the weather fish make use of floods to reach new habitats.

Control• Build defenses, such as levees, bunds, reservoirs,

weirs or dams.

• When these defenses fail, emergency measures such as sandbags or portable inflatable tubes are used.• Coastal defenses such as sea walls, beach nourishment, and barrier islands.

• Constructing underwater canals and floodways.

• Reducing the rate of deforestation should improve the incidents and severity of floods.

List of Deadliest FloodsRank Death toll Event Location Date

1 2,500,000–3,700,000 1931 China floods China 1931

2 900,000–2,000,000 1887 Yellow River (Huang He) flood China 1887

3 500,000–700,000 1938 Yellow River (Huang He) flood China 1938

4. 231,000

Banqiao Dam failure, result of Typhoon Nina. Approximately 86,000 people

died from flooding and another 145,000 died during subsequent

disease.

China 1975

5 145,000 1935 Yangtze river flood China 1935

List of Deadliest FloodsRank Death toll Event Location Date

6 more than 100,000 St. Felix's Flood, storm surge Netherlands 1530

7. 100,000 Hanoi and Red River Delta flood North Vietnam 1971

8 100,000 1911 Yangtze river flood China 1911

9 50,000–80,000 St. Lucia's flood, storm surge Netherlands 1287

10 2,400 North Sea flood, storm surge Netherlands,England, Belgium

January 31,

1953

LIMNIC ERUPTIONalso referred to as a lake overturn,

is a rare type of natural disaster in which carbon dioxide (CO2) suddenly erupts from deep lake water, suffocating wildlife, livestock and humans.

Definition

Scientists believe landslides, volcanic activity or explosions can trigger such an eruption.

LIMNIC ERUPTIONLakes in which such activity occurs

may be known as limnically active lakes or exploding lakes.

Definition

Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water.

Features of Limnically Active Lakes

• CO2-saturated incoming water• A cool lake bottom indicating an

absence of direct volcanic interaction with lake waters

• An upper and lower thermal layer with differing CO2 saturations

• Proximity to areas with volcanic activity

Cause

For a limnic eruption to occur, the lake must be nearly saturated with gas which has carbon dioxide as the major component. Once the lake is saturated with CO2, it is very unstable. A trigger is all that is needed to set off an eruption.

CauseIn any case, the trigger pushes some of the

saturated water higher in the lake, where the pressure is insufficient to keep the CO2 in solution. Bubbles start forming and the water is lifted even higher in the lake (buoyancy), where even more of the CO2 comes out of solution. This process forms a column of gas. At this point the water at the bottom of this column is pulled up by suction, and it too loses its CO2 in a runaway process. This eruption pours CO2 into the air and can also displace water to form a tsunami.

Reasons why this type of eruption is very rare:

1. There must be a source of the CO2, so only regions with volcanic activity are at risk.

2. Temperate lakes turn over each spring and fall as a result of seasonal air temperature changes, mixing water from the bottom and top of the lake, so CO2 that builds up at the bottom of the lake is brought to the top where the pressure is too low for it to stay in solution and it escapes into the atmosphere.

Reasons why this type of eruption is very rare:

3. A lake must be quite deep to have enough pressure to dissolve large volumes of CO2. So only in deep, stable, tropical, volcanic lakes are limnic eruptions possible.

Consequences1. Living organisms may experience asphyxia,

therefore leading to unconsciousness or even death.

2. Plants and vegetation which grew adjacent to the lake maybe damaged or destroyed by a tsunami cause by the eruption.

A Possible Solution

• Degassing lakes – removing gas from the lake using siphons

List of Limnic Eruptions

Rank Death toll Event Location Date

1 1,746 Lake Nyos Cameroon 1986

2 37 Lake Monoun Cameroon 1984

TSUNAMIAlso called a tsunami wave train,

and at one time referred to as a tidal wave, is a series of water waves caused by the displacement of a large volume of a body of water, usually an ocean, though it can occur in large lakes.

Definition

Generation Mechanism

1. Tsunami generated by seismic activity

Drawing of tectonic plate boundary before earthquake



Overriding plate bulges under strain, causing tectonic uplift.



Plate slips, causing subsidence and releasing energy into water.



The energy released produces tsunami waves.


2. Tsunami generated by landslides

- In the 1950s, it was discovered that larger tsunamis than had previously been believed possible could be caused by giant landslides. These phenomena rapidly displace large water volumes, as energy from falling debris or expansion transfers to the water at a rate faster than the water can absorb.

Drawback• If the first part of a tsunami to reach land

is a trough—called a drawback—rather than a wave crest, the water along the shoreline recedes dramatically, exposing normally submerged areas.

• A drawback occurs because the water propagates outwards with the trough of the wave at its front. Drawback begins before the wave arrives at an interval equal to half of the wave's period.

Drawback

Wave animation showing the initial "drawback" of surface water

List of TsunamisRank Death

toll Event Location Date

1 230,210 2004 Indian Ocean Tsunami

Indonesia, Sri Lanka, India, Maldives,

Malaysia, Somalia, Bangladesh, Thailand

26 December

, 2004

2 123,000 1908 Messina earthquake / tsunami Messina, Italy 1908

3 100,0001755 Lisbon earthquake / tsunami / fire

Portugal, Spain, Morocco, Ireland, and the United

Kingdom(Cornwall)1755

4 36,000 Caused by 1883 eruption of Krakatoa Indonesia 1883

5. 30,000 1707 Hōei earthquake Tōkaidō/Nankaido, Japan 1707

List of TsunamisRank Death toll Event Location Date

6 25,674 1868 Arica earthquake / tsunami Arica, Chile 1868

7 22,070 1896 Meiji-Sanriku earthquake Sanriku, Japan 1896

8 15,273 to 23,567

2011 Tōhoku earthquake and tsunami

Iwate/Miyagi/Fukushima, Japan

11 March, 2011

9 15,0301792 Mount Unzen eruption

in southwest Kyūshū / tsunami

Kyūshū, Japan 1792

10 12,000 1771 Great Yaeyama Tsunami Yaeyama, Okinawa, Japan 1771

Meteorological Disasters

• Blizzards• Cyclonic Storms• Droughts• Hailstorms• Heat Waves• Tornadoes

BLIZZARDS is a severe snowstorm characterized

by strong winds.

Definition

Blizzards can bring near-whiteout conditions, and can paralyze regions for days at a time, particularly where snowfall is unusual or rare. It also has negative impact on local economics.

List of Notable Blizzards

Rank Death toll (est.) Event Location Date

1 4,000 1972 Iran blizzard Iran 1972

2 926 2008 Afghanistan blizzard Afghanistan 2008

3 400 Great Blizzard of 1888 United States 1888

4 318 1993 North American Storm Complex United States 1993

5 235 Schoolhouse Blizzard United States 1888

List of Notable Blizzards

Rank Death toll (est.) Event Location Date

6 199 Hakko-da Mountains incident Japan 1902

7 144 Armistice Day Blizzard United States 1940

8 133 2008 Chinese winter storms China 2008

9 112 1995 Kazakh Blizzard Kazakhstan 1995

10 100 Northeastern United States blizzard of 1978 United States 1978

CYCLONIC STORMS Cyclone, tropical cyclone, hurricane

and typhoon are different names for the same phenomenon a cyclonic storm system that forms over the oceans.

Definition

Cyclone

A cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth.

This is usually characterized by inward spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth.

6 Main Types of Cyclone1. Polar Cyclones2. Polar Lows3. Extratropical Cyclones4. Subtropical Cyclones5. Tropical Cyclones6. Mesocyclones

Intensity Classifications of Tropical Cyclones

1. Tropical Depression- A tropical depression is an organized system of clouds and thunderstorms with a defined, closed surface circulation and maximum sustained winds of less than 17 meters per second or 38 miles per hour (61 km/h).

2. Tropical Storm- A tropical storm is an organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds between 17 meters per second (39 miles per hour (63 km/h)) and 32 meters per second (73 miles per hour (117 km/h).

Intensity Classifications of Tropical Cyclones

3. Hurricane or Typhoon- A hurricane or typhoon (sometimes simply referred to as a tropical cyclone, as opposed to a depression or storm) is a system with sustained winds of at least 33 metres per second) or 74 miles per hour (119 km/h).

Effects• Tropical cyclones out at sea cause large

waves, heavy rain, and high winds, disrupting international shipping and, at times, causing shipwrecks.

• On land, strong winds can damage or destroy vehicles, buildings, bridges, and other outside objects, turning loose debris into deadly flying projectiles.

Effects• The storm surge or the increase in sea

level due to the cyclone.• The broad rotation of a landfalling

tropical cyclone, and vertical wind shear at its periphery, spawns tornadoes.

• Tropical cyclones significantly interrupt infrastructure, leading to power outages, bridge destruction, and the hampering of reconstruction efforts.

Effects• Death• Flooding• Risk in disease propagation like

mosquito-borne illnesses.

Benefits• They may bring much-needed precipitation

in dry regions.

• Tropical cyclones also help maintain the global heat balance by moving warm, moist tropical air to the middle latitudes and Polar Regions.

Benefits• The storm surge and winds of hurricanes

may be destructive to human-made structures, but they also stir up the waters of coastal estuaries, which are typically important fish breeding locales.

• Tropical cyclone destruction spurs redevelopment, greatly increasing local property values.

List of Cyclones (including hurricanes)Rank Death toll Event Location Date

1 500,000 1970 Bhola cycloneEast

Pakistan, Pakistan (now Bangladesh)

November 13, 1970

2 300,000 1839 Indian cyclone India November 25, 1839

3 300,000 1737 Calcutta cyclone India October 7, 1737

4 210,000Super Typhoon Nina—contributed to Banqiao

Dam failureChina August 7,

1975

5 200,000 Great Backerganj Cyclone of 1876

present day Bangladesh

October 30, 1876

List of Cyclones (including hurricanes)Rank Death


6. ~146,000 Cyclone Nargis Myanmar May 2, 2008

7 138,866 1991 Bangladesh cyclone Bangladesh April 29,

1991

8 100,000 1882 Bombay cyclone Bombay, India 1882

9 60,000 1922 Swatow Typhoon China August 1, 1922

10 60,000 1864 Calcutta Cyclone India October 5, 1864

DROUGHT Is an extended period of months or

years when a region notes a deficiency in its water supply.

Definition

Generally, this occurs when a region receives consistently below average precipitation.

Types of Drought1. Meteorological Drought

- is brought about when there is a prolonged period with less than average precipitation.

2. Agricultural Drought- are droughts that affect crop production or the ecology of the range.

3. Hydrological Drought- is brought about when the water reserves available in sources such as aquifers, lakes and reservoirs fall below statistical average.

Causes• Reduce amount of rainfall• Oceanic and atmospheric weather

cycles such as the El Niño – Southern Oscillation (ENSO)

• Human activity can directly trigger exacerbating factors such as over farming, excessive irrigation, deforestation, and erosion adversely impact the ability of the land to capture and hold water.

Causes• Paradoxically, some proposed solutions

to global warming that focus on more active techniques, solar radiation management through the use of a space sunshade for one, may also carry with them increased chances of drought.

Effects of Drought• Diminished crop growth or yield productions and carrying

capacity for livestock

• Dust bowls• Dust storms• Famine due to lack of water for irrigation• Habitat damage• Malnutrition, dehydration and related diseases• Mass migration

Effects of Drought• Reduced electricity production due to reduced water flow

through hydroelectric dams

• Shortages of water for industrial users• Snakes migration and increases in snakebites• Social unrest• War over natural resources, including water and food• Wildfires

Drought Protection and Relief• Dams• Cloud seeding • Desalination of sea water for irrigation

or consumption.

• Drought Monitoring• Land Use

Drought Protection and Relief• Outdoor water-use restriction • Rainwater harvesting • Recycled water • Transvasement

HAILSTORM A type of storm that precipitates

chunks of ice. Hailstorms usually occur during regular thunder storms.

Definition

While most of the hail that precipitates from the clouds is fairly small and virtually harmless, there have been cases of hail greater than 2 inches diameter that caused much damage and injuries.

Effects on Human Society• Hail damage to roofs often goes unnoticed until

further structural damage is seen, such as leaks or cracks.

• Hail is also a common nuisance to drivers of automobiles, severely denting the vehicle and cracking or even shattering windshields & windows.

• In Aviation, hail is one of the most significant thunderstorm hazards to aircraft.

Effects on Human Society• In Agriculture, hail can cause serious damage,

notably to automobiles, aircraft, skylights, glass-roofed structures, livestock, and most commonly, farmers' crops.

• Rarely, massive hailstones have been known to cause concussions or fatal head trauma.

HEAT WAVE Is a prolonged period of

excessively hot weather, which may be accompanied by high humidity.

Definition

Effects• Hyperthermia• Heat edema • Heat rash• Heat cramps• Heat syncope• Heat exhaustion

Effects• Psychological and Sociological Effects• Power Outrage • Wildfires• Physical Damage

List of Heat WavesRank Death toll Event Location Date

1 56,000 2010 Russian heat wave Russia 2010

2 40,000 2003 European heat wave Europe 2003

3 5,000–10,000

1988 United States heat wave United States 1988

4 1,700 1980 United States heat wave United States 1980

List of Heat WavesRank Death toll Event Location Date

5 1,648 2010 Japanese heat wave Japan 2010

6 1,500 2003 Southern India heat wave India 2003

7 946 1955 Los Angeles heat wave United States 1955

8 891 1972 New York City heat wave United States 1972

9 739 1995 Chicago heat wave United States 1995

TORNADOES is a violent, dangerous,

rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud.

Definition

Life Cycle• Supercell Relationship

- Tornadoes often develop from a class of thunderstorms known as supercells. Supercells contain mesocyclones, an area of organized rotation a few miles up in the atmosphere, usually 1–6 miles (2–10 km) across.

• Formation- As the mesocyclone approaches the ground, a visible condensation funnel appears to descend from the base of the storm, often from a rotating wall cloud.

Life Cycle• Maturity

- Initially, the tornado has a good source of warm, moist inflow to power it, so it grows until it reaches the "mature stage". This can last anywhere from a few minutes to more than an hour, and during that time a tornado often causes the most damage, and in rare cases can be more than one mile (1.6 km) across.

• Demise- As the mesocyclone approaches the ground, a visible condensation funnel appears to descend from the base of the storm, often from a rotating wall cloud.

Types of Tornadoes1. Multiple Vortex

- A multiple-vortex tornado is a type of tornado in which two or more columns of spinning air rotate around a common center.

Types of Tornadoes2. Waterspout

- A waterspout is defined by the National Weather Service as a tornado over water.

Types of Tornadoes2 Kinds of Waterspout Tornadoes:

- are less severe but far more common, and are similar to dust devils and landspouts.

a. Fair Weather Waterspout

b. Tornadic Waterspout- are stronger tornadoes over water.

Types of Tornadoes3. Landspout

- or dust-tube tornado, is a tornado not associated with a mesocyclone. The name stems from their characterization as a "fair weather waterspout on land“.

4. Similar Circulationa. Gustnado

- A gustnado, or gust front tornado, is a small, vertical swirl associated with a gust front or downburst.

Types of Tornadoesb. Dust Devil

- A dust devil resembles a tornado in that it is a vertical swirling column of air. However, they form under clear skies and are no stronger than the weakest tornadoes.

Types of Tornadoesc. Fire Swirls and Steam Devils

- Small-scale, tornado-like circulations can occur near any intense surface heat source. Those that occur near intense wildfires are called fire whirls.- A steam devil is a rotating updraft that involves steam or smoke. Steam devils are very rare. They most often form from smoke issuing from a power plant smokestack.

List of TornadoesRank Death


1 1,300 The Daulatpur-Salturia Tornado Manikganj, Bangladesh April 26,

1989

2 923 1969 East Pakistan Tornado

East Pakistan, Pakistan (now

Bangladesh)1969

3 695 The Tri-State TornadoUnited

States (Missouri–Illinois–Indiana)

March 18, 1925

4 681 1973 Dhaka Tornado Bangladesh 1973

5 600 The Valetta, Malta Tornado Malta 1551

List of TornadoesRank Death


6. 500 The Sicily Tornado Sicily, Two Sicilies (now Italy) 1851

6. 500 The Narail-Magura TornadoesJessore, East

Pakistan, Pakistan (now Bangladesh)

1964

6. 500 The Comoro Tornado Comoro 1951

9. 440 The Tangail Tornado Bangladesh 1988

10. 400 The Ivanovo-Yaroslavl, Russia, Tornado

Soviet Union (now Russia) 1984

Fires

• Wildfires

WILDFIRES

is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area.

Definition

WILDFIRES Other names such as brush

fire, bushfire, forest fire, desert fire,grass fire, hill fire, peat fire, vegetation fire, veldfire, and wild land fire may be used to describe the same phenomenon depending on the type of vegetation being burned.

Definition

Wildfires are characterized in terms of:• the cause of ignition• their physical properties such as speed

of propagation

• the combustible material present

• the effect of weather on the fire

Causes• Four major natural causes of wildfire ignition

1. lightning

• Human Causes

2. volcanic eruption3. sparks from rockfalls

4. spontaneous combustion

arson discarded cigarettes sparks from equipment power line arcs

Causes• Coal seam fires

• Abandoned logging roads overgrown by vegetation may act as fire corridors.

• Slash and burn clearings• Forested areas cleared by logging encourage

the dominance of flammable grasses.

• Heat waves, droughts, cyclical climate changes and regional weather patterns

Fuel Types• Ground fires are fed by subterranean

roots, duff and other buried organic matter.

• Crawling or surface fires are fueled by low-lying vegetation such as leaf and timber litter, debris, grass, and low-lying shrubbery.

Fuel Types• Ladder fires consume material between

low-level vegetation and tree canopies, such as small trees, downed logs, and vines.

• Crown, canopy, or aerial fires burn suspended material at the canopy level, such as tall trees, vines, and mosses.

Prevention• Fire-stick farming

• Vegetation may be burned periodically to maintain high species diversity, and frequent burning of surface fuels limits fuel accumulation, thereby reducing the risk of crown fires.

• Fire prevention campaign like posters highlighting the role of human carelessness in forest fires.

• Wildland fire use

Prevention• Chain saws and large equipment can be used

to thin out ladder fuels and shred trees and vegetation to mulch.

• Controlled burns

• Wildfire models may be used to predict and compare the benefits of different fuel treatments on future wildfire spread.

Detection• Fire lookout and scanning towers• Public hotlines• ground and aerial patrols• Electronic and detection system such as

wireless sensor networks• Satellite-mounted sensors• Combining remote-sensing data from

satellite sources

Suppression• In less developed nations the techniques used

can be as simple as throwing sand or beating the fire with sticks or palm fronds.

• In more advanced nations, the suppression methods vary due to increased technological capacity. Silver iodide can be used to encourage snow fall, while fire retardants and water can be dropped onto fires by unmanned aerial vehicles, planes, and helicopters.

Suppression• Wildfire modeling - can ultimately aid wildfire

suppression, increase the safety of firefighters and the public, and minimize damage.

List of Wildfires and BushfiresRank Death


1 1,200–2,500 Peshtigo Fire, Wisconsin United States October 8,

1871

2 1,200 Kursha-2 Fire Soviet Union August 3, 1936

3 453 Cloquet Fire, Minnesota United States October 12, 1918

4 418 Great Hinckley Fire, Minnesota United States September 1, 1894

5 282 Thumb Fire, Michigan United States September 5, 1881

6 273 Matheson Fire, Ontario Canada July 29, 1916

List of Wildfires and BushfiresRank Death


7 240 Sumatra and Kalimantan Fires Indonesia 1997

8 230 Landes region France 1949

9 213 Black Dragon Fire China May 1987

10 173 Black Saturday bushfires Australia February 7 – March 14, 2009

11 167 Fires of Needle Ridge United States February 12 – April 4, 1980

12 71 Black Friday bushfires (1939) Australia January 13, 1939

Health Disaster

• Epidemics• Famines

EPIDEMICS Occurs when new cases of a

certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience.

Definition

A few cases of a very rare disease may be classified as an epidemic, while many cases of a common disease (such as the common cold) would not.

In the last hundred years, significant pandemics include:

• The 1918 Spanish flu pandemic, killing an estimated 50 million people worldwide

• The 1957-58 Asian flu pandemic, which killed an estimated 1 million people

• The 1968-69 Hong Kong flu pandemic

• The 2002-3 SARS pandemic• The AIDS pandemic, beginning in 1959

• The H1N1 Influenza (Swine Flu) Pandemic 2009-2010

Other diseases that spread more slowly, but are still considered to be global health emergencies by the World Health Organization (WHO) include:

• XDR TB, a strain of tuberculosis that is extensively resistant to drug treatments

• Malaria, which kills an estimated 1.6 million people each year

• Ebola hemorrhagic fever, which has claimed hundreds of victims in Africa in several outbreaks.

List of PandemicsRank Death toll

(estimate) Event Location Date

1. 100,000,000 approx. Black Death Asia, Europe, Africa 1300s–1720s

2. 50,000,000–100,000,000 Spanish Flu Worldwide 1918–1920

3. 40,000,000–100,000,000 Plague of Justinian Asia, Europe, Africa 540–590

4. 12,000,000 Third

Pandemic of Bubonic Plague

Worldwide 1850s–1950s

5. 5,000,000 Antonine Plague Roman Empire 165–180

6. 4,000,000 Asian Flu Worldwide 1956–1958

FAMINES is a widespread scarcity of food

that may apply to any faunal species.

Definition

This phenomenon is usually accompanied or followed by regional malnutrition, starvation, epidemic, and increased mortality.

Definitions of famines based on 3 different categories:

1. food supply-based2. food-consumed based3. mortality-based definitions

Some definitions of famines are:• Blix• Brown and Eckholm • Scrimshaw• Ravallion• Cuny

Some elements make a particular region more vulnerable to famine. These include:

• Poverty• Inappropriate physical infrastructure• Inappropriate social infrastructure• A suppressive political regime• A weak or under-prepared government

Causes• imbalance of food production• agricultural problems such as drought,

crop failure, or pestilence• changing weather patterns• the ineffectiveness of governments in

dealing with crises, wars, and epidemic diseases

• volcanism

Famine Prevention• The effort to bring modern agricultural

techniques found in the West, such as nitrogen fertilizers and pesticides to Asia, called the Green Revolution, resulted in decreases in malnutrition similar to those seen earlier in Western nations.• Existing infrastructure and institution such as system of roads or public seed companies that made seeds available.

Famine Prevention

• Supporting farmers in areas of food insecurity, through such measures as free or subsidized fertilizers and seeds, increases food harvest and reduces food prices.

Famine Relief• Deficient micronutrient can be provided

through fortifying foods.• There is a growing realization among aid groups

that giving cash or cash vouchers instead of food is a cheaper, faster, and more efficient way to deliver help to the hungry, particularly in areas where food is available but unaffordable.

Famine Relief

• For people in a drought living a long way from and with limited access to markets, delivering food may be the most appropriate way to help.

List of FaminesRank Death toll Event Location Date

1 15,000,000–43,000,000 Great Chinese Famine China 1958–1961

2 24,000,000 Chinese Famine of 1907 China 1907

3 19,000,000 Indian Famine British India 1896–1902

4 15,000,000Bengal famine of

1770, including Bihar & Orissa

India 1769–1771

5 13,000,000 Northern Chinese Famine China 1876–1879

List of FaminesRank Death toll Event Location Date

6 10,000,000 Indian Great Famine of 1876–78 India 1876–1879

7 7,500,000 Great European Famine Europe (all) 1315–1317

8 7,000,000-10,000,000

Soviet famine of 1932–

1933 (Holodomor)Soviet Union 1932–1934

9 5,000,000 Chinese Famine of 1936 China 1936

10 5,000,000 Russian famine of 1921 Russia, Ukraine 1921–1922

Space Disaster

• Impact Events• Solar Flares• Gamma Ray Burst

IMPACT EVENTSIs the collision of a large

meteorite, asteroid, comet, or other celestial object with the Earth or another planet.

Definition

Sizes and Frequencies• Asteroids with a 1 km (0.62 mi) diameter strike the

Earth every 500,000 years on average.

• Large collisions – with 5 km (3 mi) objects – happen approximately once every ten million years.

• The last known impact of an object of 10 km (6 mi) or more in diameter was at the Cretaceous–Tertiary extinction event 65 million years ago.

Sizes and Frequencies• Asteroids with diameters of 5 to 10 m (16 to 33 ft)

enter the Earth's atmosphere approximately once per year.

• Objects with diameters over 50 m (164 ft) strike the Earth approximately once every thousand years.

• Objects with diameters smaller than 10 m (33 ft) are called meteoroids (or meteorites if they strike the ground). An estimated 500 meteorites reach the earth’s surface each year.

Effects• A few of these impacts may have caused

massive climate change and the extinction of large numbers of plant and animal species.

• Changes on planet’s surface topology due to asteroid impacts.

• Recent studies have shown that several consecutive impacts can have effect on the dynamo mechanism at a planet's core.

SOLAR FLARES

Is a phenomenon where the sun suddenly releases a great amount of solar radiation, much more than normal.

Definition

Classification• According to peak flux of 100-800 X-rays near Earth

1. A2. B3. C4. M5. X

• According to Intensity1. Fair2. Normal3. Brilliant

Cause• Flares occur when accelerated charged

particles, mainly electrons, interact with the plasma medium. Scientific research has shown that the phenomenon of magnetic reconnection is responsible for the acceleration of the charged particles.

Hazards• Solar flares strongly influence the local space weather

in the vicinity of the Earth. They can produce streams of highly energetic particles in the solar wind, known as a solar proton event, or "coronal mass ejection" (CME).

• A massive solar flare could knock out electric power for months.

• The soft X-ray flux of X class flares increases the ionization of the upper atmosphere, which can interfere with short-wave radio communication and can heat the outer atmosphere and thus increase the drag on low orbiting satellites, leading to orbital decay.

Massive X6.9 class solar flare, August 9, 2011. While this flare produced a coronal mass ejection (CME), this CME did not travelled towards the Earth, and no local effects were recorded.

Some known solar flares include:• An X20 event on August 16, 1989• The most powerful flare ever recorded, on Nov. 4,

2003, estimated at between X40 and X45

• The most powerful flare in the past 500 years is believed to have occurred in September 1, 1859.

• Other large solar flares also occurred on April 2, 2001 (X20), October 28, 2003 (X17.2 & X10), September 7, 2005 (X17), February 17, 2011 (X2), and August 10, 2011 (X6.9).

GAMMA RAY BURSTS (GRBs)Are flashes of gamma rays

associated with extremely energetic explosions that have been observed in distant galaxies.

Definition

GRB are the most power explosion that occur in universe that release enormous amount of energy in millisecond or longing for ten seconds.

2 Categories1. Short Gamma Ray Burst

- events with a duration of less than about two seconds

2. Long Gamma Ray Burst - events that last 2 seconds or longer sometimes 100 seconds

White dwarf nova explosion emits "shocking" burst of gamma rays

Rates and Potential Effects on Life on Earth

• Measuring the exact rate is difficult, but for a galaxy of approximately the same size as the Milky Way, the expected rate (for long GRBs) is about one burst every 100,000 to 1,000,000 years. Only a small percentage of these would be beamed towards Earth.


• Potential effect comparing Deinococcus radiodurans The first impact is a flash of gamma rays. The flash

can damage even the most radiation resistant organism known, the bacterium Deinococcus radiodurans.

For a planet with a thin atmosphere, the gamma flash could kill 90% of D. radiodurans from distances up to three times our galaxy’s width.


• Potential effect comparing Deinococcus radiodurans For thick atmosphere planets, a gamma-ray burst’s

ultraviolet rays would kill 90% of D. radiodurans at distances ranging from 13,000 to 62,000 light years.

Life surviving that onslaught would have to contend with a third effect, depletion of the atmosphere’s protective ozone layer by the burst.


• Hypothetical Effect of GRBs in the past

GRBs close enough to affect life in some way might occur once every five million years or so - around a thousand times since life began.

The devastating Ordovician Mass Extinction of 450 million years ago may have been caused by a GRB.


• Hypothetical Effect of GRBs in the future

The real danger comes from Wolf-Rayet stars regarded by astronomers as ticking bombs. When such stars transition to supernovas, they may emit intense beams of gamma rays, and if Earth were to lie in the beam zone, devastating effects may occur.

If WR 104 were to hit Earth with a burst of 10 seconds duration, its gamma rays could deplete about 25 percent of the world's ozone layer.


• Effects After Exposure to the GRBs on Earth’s Atmosphere

Longer-term, gamma ray energy may cause chemical reactions involving nitrogen and oxygen molecules which may create nitrogen oxide then nitrogen dioxide gas, causing photochemical smog. The GRB may produce enough of the gas to cover the sky and darken it.

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Natural Calamities (Group 8)